Here they are. one 3 ton and one 2.5 ton. Carrier ARHI 3656405 58CVA909-16 80% Infinity 2 stage gas furnace CNPVP3717ATA tin plated copper coil 24ACC636A003 3 ton Comfort series A/C TP-PAC EDGE Programmable Thermostat Cost $6380 58CVA070-12 80% Infinity 2 stage Gas furnace CNPVP3014ATA tin plated copper coil 24ACC630A003 2.5 ton Comfort series A/C TP-PAC EDGE Programmable Thermostat Cost $5885 Both Carrier systems come with Perfomance series media cabinet. Trane: 15i A/C systems and XV80 furnaces 3233365 Active Coil (Mix-Match) ASPEN TRANE 4TTX5030A1 ASPEN MANUFACTURING C(A,C,D,E)30D44+TDR *UD060R9V3 30000 13.10 16.00 1 RCU-A-CB 216 Yes Cost = $5825 3233463 Active Coil (Mix-Match) ASPEN TRANE 4TTX5036A1 ASPEN MANUFACTURING C(A,C,D,E)36D44+TDR *UD100R9V5 36000 13.30 16.50 1 RCU-A-CB 251 Yes Cost = $6023 Tcon802 thermostats Aprilaire 4200 series SPaceguard media cabinets 2 at $225 each Both say I have super air flow and neither will change the line sets. They are in 'great shape' and run through finished space. Will clean, flush, etc. Incl is new electric disconnect and poly pad for each system. The above costs are the prices I pay the contractor. The are withing $50 in total, once I include the filter media. I also get a federal tax credit of $1500 plus a Va. state grant of $2000. What tips the scales in favor of one over the other?

York YM9M isn't variable speed. Request a Honeywell VisionPRO IAQ (preferably, if not the VisionPRO 8000 will be fine) as it can slow the blowers down to dehumidify on demand and is an overall nice thermostat. The Affinity is a nice line of units, so you may want to look at the YCB 13 SEER Affinity line. Not a big fan of 2-stage A/C. I think single stage properly sized is more than sufficient with dehumidification controls (the IAQ). It's never a bad idea to get 2-3 bids for a job like this. Did they size the equipment per a load calculation (called Manual J)? Did they make sure your ductwork was adequate? More goes into this than just the equipment.

How much extra are you being quoted? Right off the cuff I'd say I would go for the heat aspect as it would give you greater control over marginal heating needs and spring and fall, and might need some heat in the early morning or late evening, but cooling during the day.

12" return is almost definitely too large for the basement. I have a 6" return in my basement, and I have actually found it to draw ~200-240 cfm (using a barometer) -- plenty in my case with just a few supply outlets. In your case, I have no way of knowing for sure, but I assume it's piped directly (or near) to the inlet of the furnace blower compartment, in which case there is a lot of pressure and it's sucking in a lot of air and making the basement quite negative (not a good thing). So your basement return in that state may have been drawing close to, if not more than, half of the return air the entire system requires. Is the basement floorplan open to the rest of the home or closed off? If typically closed off, I wouldn't be surprised if the basement door had a tendency to close itself when the system was operating. I suppose putting cardboard over half of the grille is one way to reduce its intake capacity. Your older furnace does not (presumably) have a variable speed blower that will vary its RPM in order to maintain a specific CFM setting. That means that while you are noticing more airflow from the rest of the returns throughout the home, in totality your system is receiving less airflow -- no, not a good thing considering your ductwork is likely undersized to begin with. You have decreased its return capacity. To get the SAME (total) airflow from the rest of the returns throughout the home that were not previously drawing as much air generally requires the system to operate at an increased static; with older PSC type blower motors (non variable-speed), this results in decreased airflow. Hence variable speed motors are often termed "constant CFM" as they can adjust (increase) their speed to maintain a constant airflow (cfm) when subjected to as much as 0.8-1.0" of external static pressure (vs. conventional blowers max. of 0.5", which many duct systems are nowhere close to achieving despite it being the standard "design" figure). You can think of the ESP number as a measure of resistance to airflow, in a sense. The fact that you say the (supply?) ductwork is now much warmer is both concerning and telling. It is unwise for me to say much more than that as I am not there to evaluate your system design and give an accurate assessment of the ductwork design/layout, etc. But it suffices to say, with the info you've provided us, your return ductwork is now more restrictive, which would exacerbate any existing airflow issues. You do say it met the set point without tripping the high limit. Please let us know how the system performs as it gets colder out and the system runs more often in its present state. I would like to ask what made you consider replacing the systems (and proceeding to get 8 proposals) in the first place? Are there functional problems with the existing equipment (besides most likely being oversized) or other comfort issues? By now we have at least established that it is likely the existing equipment is a bit oversized and the existing ductwork is marginal -- but that is (unfortunately) exceedingly common on most residential construction. Are you after more efficiency, better comfort, both? It helps us to help you when we know more about your current system's performance. Lastly, I would not factor online reviews into your decision too much. An air conditioner or furnace is not like most appliances (such as a refrigerator) in that the installation practices and quality can make or break even the best equipment selection. There is a good chance that many (but not all) of the negative reviews you read were due to installation errors. This post was edited by ryanhughes on Fri, Nov 22, 13 at 9:51